Transpose(Normalize): Output schema added in Transpose only accepts string datatype for all the fields in output schema added

The output schema added only accepts the fields with string datatype only, if the input schema of source has date(1986-02-05) datatype format then fields to be mapped are accepting string values and throws error if other than string datatype is added.

Steps to reproduce:

1. Launch the latest CDAP (6.8.0)

2. Open Transpose plugin under transform.

3. Establish connection from BigQuery source to Transpose to BigQuery sink.

4. Fill the properties of Transpose by providing mandatory fields to be mapped with any date datatype fields along with fields to be normalized and add the output schema any date field with ‘Date’ datatype and click on validate.

5. Error is displayed as all the output schema fields must be of string datatype.

6. Deploy the pipeline with all string datatype in output schema.

7. Attached the source BQ table and Generated BQ table screenshots.

Expected: If date datatype field is available in input source schema, then all the supported datatypes should be accepted in output schema for fields added.
Actual: If date datatype field is available in input source schema, then all the supported datatypes not accepting in output schema for fields to be added for mapping. Since it is accepting string the date value is shown properly in BigQuery table created.